Wireless networks continue to evolve to support new services and increased transmission rates as new communication technologies develop and standardize. A representative wireless network for a wireless network service provider can include support for one or more releases of the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) wireless communication standard and LTE-Advanced wireless communication standard. This representative wireless network can support packet switched connections (voice or data) through an LTE or LTE-Advanced network.
An LTE (LTE-Advanced) wireless network can support high rate packet communication to multiple mobile wireless devices simultaneously within a geographic area. The radio frequency spectrum used for communication to the multiple mobile wireless devices can be shared among the multiple mobile wireless devices using an orthogonal frequency division multiplexing (OFDM) transmission method. A transceiver (transmitter/receiver) in a mobile wireless device can adapt to radio frequency spectral variation using the OFDM transmission method, which can divide the occupied radio frequency spectrum into a set of parallel narrower bandwidth and lower data rate communication sub-channels transmitted on parallel subcarriers, and each sub-channel can experience approximately flat frequency spectrum fading. An OFDM communication system can divide transmissions into a series of successive OFDM symbols in time, with each OFDM symbol providing multiple sub-channels centered at different frequencies simultaneously. A transmission “resource element” (RE) can be considered a unit of transmission capacity on a single sub-channel within a single OFDM symbol, and the wireless network can allocate multiple RE across multiple sub-channels among multiple wireless devices dynamically over time. The wireless network can regularly broadcast control information about the allocation of the RE to the multiple wireless devices within a geographic area served by a radio frequency access system of the wireless network. The control information itself can be transmitted using a subset of the total available RE, and the number of RE available to support communication of control information can limit the total number of mobile wireless devices that can be connected simultaneously to the wireless network.
Communication systems can be sensitive to errors that can occur in the control information received at the wireless devices, and the wireless network can use different rates of error correction coding to protect the control information during transmission and reception by the mobile wireless device in the presence of noise and interference. Received signal quality at a mobile wireless device can vary significantly based on the location of the mobile wireless device with respect to a transmitting radio frequency access system located in an access network portion of the wireless network and also based on the amount of noise and interference received by the mobile wireless device. Mobile wireless devices located at a greater distance, such as nearer the edge of a geographic coverage area of the access network transmitter, can receive weaker signals than mobile wireless devices located closer to the access network transmitter. As the control information can be broadcast simultaneously to all of the multiple wireless devices served by the access network transmitter, the transmit power used for control channel transmissions can be the same for the different multiple wireless devices, while the amount of error correction coding applied can be varied to better protect transmissions to the different mobile wireless devices. Specifically more RE can be allocated for communication of control information to mobile wireless devices with lower received signal quality, and fewer RE can be allocated to control channel messages sent to mobile wireless devices with higher received signal quality. The same RE can be allocated to multiple mobile wireless devices by sharing the same frequency band/time slot occupied by the RE using a form of spatial division multiplexing. Multi-user multiple input multiple output (MU-MIMO) transmission methods can be applied to transmissions of the control information to share selected RE among multiple mobile wireless devices and to increase the total number of mobile wireless devices that can be simultaneously supported by a radio sector of the wireless network.